It is known to drive a bending wave loudspeaker panel near its centre by exciter[s] providing out of plane forces, offering useful efficiency, see, for example, International Application WO97/09842 to the present applicants.
It is also known that a transparent bending wave diaphragm may be combined with a display, and driven near its periphery, with defined boundary conditions. In such devices, the excitation is normal to the panel diaphragm plane, i.e. out of plane. This excitation method unfortunately occupies a proportion of the overall panel area, see for example International Application WO00/02417 to the present applicants.
It is also known that a bending wave panel speaker may be driven by a bending moment where the driving force is applied using the principle of a fulcrum, such methods including the use of a right angle lever with a fulcrum or simple support positioned inboard of the lever, see International Application WO00/13464 to the present applicants.
It is an object of the invention to provide a method and means whereby a simple lever couple may be used to present bending forces to a bending wave panel.